Specula are used to examine interior portions of a body through cavities. The specula is placed into the cavity and expanded to open the cavity while at the same time permitting a physician to view the inside of the cavity. Various types and designs of specula are well known. A typical type is disclosed in U.S. Pat. No. 5,072,720, wherein a pair of duck-bill blades are slidably attached to each other. The blades are inserted into a body cavity and manipulated to move the blades apart from each other to form a cavity therebetween. The physician then views the cavity walls through a space formed between the blades.
Another design for a speculum is disclosed in U.S. Pat. No. 5,916,151, wherein four blades spaced apart are connected by cables to a pair of rings, at a center portion thereof and an end portion. The distal ends of the blades are generally in a side by side relationship and movable laterally with respect to each other between a contracted position wherein the distal ends are closely adjacent to each other to an expanded condition wherein the blades are separated from each other. The blades are placed into the body cavity in the contracted position and then manipulated, via the cables, to the extended condition to open up the cavity.
While these specula perform satisfactorily in most conditions, their insertion and manipulation can cause discomfort to the patient. The disadvantage of the older duck-bill type specula is that the peripheral edge of the blades can cause discomfort during insertions and removals. Such blades can also pinch interior walls when the blades are moved back together during removal of the speculum following an observation by the physician.
A disadvantage with the four blade design is that the blades hang loose in the cables, where it is possible for one or more of the blades to extend in undesired directions during insertion or during manipulation causing discomfort. Such a design requires the physician to manually hold the blades together during insertion and monitor closely the positions of the blades.